An oscillation wavelength of semiconductor laser, which has been frequently used as an image exposing device of an electrophotographic photosensitive member is, at present, a long wavelength such as 650 to 820 nm. Accordingly, development of an electrophotographic photosensitive member having high sensitivity to light having such a long wavelength has been advanced.
A phthalocyanine pigment is effective as a charge-generating substance having high sensitivity to light having a wavelength in such a long-wavelength region. In particular, oxytitanium phthalocyanine and a gallium phthalocyanine have excellent sensitivity characteristics, and various crystal forms thereof have been reported heretofore.
An electrophotographic photosensitive member using the phthalocyanine pigment has an excellent sensitivity characteristic. However, the electrophotographic photosensitive member involves the following problem. A produced photo-carrier is liable to remain on its photosensitive layer and is liable to serve as one kind of memory to cause an electric potential variation such as a ghost phenomenon.
In addition, Patent Literature 1 reports the following. When the pigment and a specific organic electron acceptor are subjected to a wet pulverization treatment, the organic electron acceptor is taken in a surface of the crystal simultaneously with crystal transformation, and hence the electrophotographic characteristics are improved.
In addition, Patent Literatures 2 and 3 disclose that an azotized calixarene compound or a resorcinarene compound is used in the photosensitive layer. The compound is used in an attempt to alleviate the ghost phenomenon.